Score and tool for forming the score

ABSTRACT

A score having improved anti-fracture characteristics formed by a scoring punch including inclined sides merging at a flat bottom face. At least one of the sides is formed with a horizontal ledge parallel to the flat scoring face and located in vertical spaced relation from the face.

United States Patent [191 Hollt, Jr. et al.

[ SCORE AND TOOL FOR FORMING THE SCORE [75] Inventors: Albert J. Holk, Jr., Frankfort; Jerry D. Hawkins, Country Club Hills, both of I11.

[73] Assignee: Continental Can Company, Inc.,

New York, NY.

[22] Filed: June 18, 1973 [21] Appl. No.: 370,903

[52] U.S.Cl. 113/1 F; 113/15 A; 113/121 C [51] Int. Cl BZld 51/00 [58] Field of Search......... 29/190; 83/6, 7; 1131/] F,

113/15 A, 15 R, 116 Y, 120 Q, 121 C [56] References Cited UNITED STATES PATENTS 3,583,348 6/1971 Brown 113/15 A Aug. 12, 1975 3,728,980 4/1973 Fraze 113/1 F Primary Examiner-C. W. Lanham Assistant ExaminerRobert M. Rogers Attorney, Agent, or Firm-Diller, Brown, Ramik 8L Wight [57] ABSTRACT A score having improved anti-fracture characteristics formed by a scoring punch including inclined sides merging at a flat bottom face. At least one of the sides is formed with a horizontal ledge parallel to the flat scoring face and located in vertical spaced relation from the face.

8 Claims, 3 Drawing Figures sum PATENTEI] AUG] 2W5 PATENTEB 81 2W5 3, 898.944

SHEET 2 FIG.2

SCORE AND TOOL FOR FORMING THE SCORE BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to scoring of sheet metal to form a weakening line capable of being sev ered by a minimum force.

weakening lines are used in containers for defining a removable panel section in the panel of the end closure. These weakening lines are generally formed by scoring in a manner such that the sheet metal is crushed to a predetermined thickness. The crushed thickness remaining is generally designated as the residual. In easy opening container structures it is essential that the residual is maintained at a minimum to facilitate the manual opening of the container. At the same time the residual must be sufficiently strong so as to resist fracture during normal handling so that the container remains tightly sealed until opening.

These conditions have been difficult to achieve and in particular when the end closure is made from a relative non-ductile material such as steel. Although it should be understood that care must also be taken to prevent inadvertent fracture when the material is aluminum.

The fracture during normal handling is believed to be caused by work hardening stresses or the like created during the scoring. I-Ieretofore, it has been common practice to provide an additional score of lesser residual than the primary score. These lesser residual scores are known as anti-fracture scores and are not intended to provide a weakening line along which the end unit panel is to be severed. The anti-fracture scores have been concentrically located in radially spaced relation to the primary score line.

The radial spacing of the anti-fracture score from the primary score or weakening is not always convenient and frequently interferes with other structures which may be incorporated into the end unit.

By the present invention there is provided a primary score incorporating an anti-fracture means which is not located in radial spaced relation to the primary score. This is accomplished by a single score having a crosssection including a pair of inclined walls merging to ward a scoring face which is spaced from one surface of the panel to provide a residual capable of being severed. At least one of the inclined walls has two offset sections connected by a land or ledge which is vertically spaced from the scoring face.

The above described score cross-section is accomplished by a scoring tool shaped generally complementary to the score.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a greatly enlarged fragmentary crosssectional view of the scoring tools and the score formed thereby.

FIG. 2 is a greatly enlarged photomicrograph of the score formed with the tooling having the structure shown in FIG. 1.

FIG. 3 is a greatly enlarged fragmentary crosssectional view of another embodiment of the invention.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT As shown the scoring tool of the present invention comprises a punch 11 and an anvil 12. The punch 11 includes a projecting rib 13 having equilateral inclined sides'14 and 16 which taper toward a horizontally disposed flat scoring face 17. The inclined side wall 14 includes a horizontal land or ledge 18 spaced intermediate the scoring face 17'and the base 19 of the rib 13. The land 18 divides the side wall into two offset and parallel side sections 14a and 14b.

The anvil 12 has a flat face 22 located opposite the punch 11 and is adapted to support the sheet metal which may be in the form of an end closure thereon. The punch 11 and anvil 12 are mounted in a press for movement toward and away from each between a closed and open position.

Upon movement to the closed position the rib l3 penetrates the surface of the sheet metal so as to score the sheet material by crushing and compressing the material to provide a residual which is of a thickness capable of being severed as by means of a pushing or pulling force applied by a tab or the like. The outline of the score 135 which is formed by the scoring .tool 10 is generally complementary to the outline of the latter.

For convenience the walls defining the score 138 are designated by the same reference characters as those on the walls of the scoring rib 13 but with suffix S appended thereto. The score 138 includes converging sides 16 and 14a-14b of which the latter are joined by a ledge 185. The bottom of the score has a face 178.

It is to be noted that the residual X is of a depth capable of being easily severed. Also the land 188 is spaced along the wall 148 so that fracture does not occur along the line.

FIG. 2 is a reproduction of a photomicrograph at X magnification through a sheet of metal having a score made by the tooling of the structure shown in FIG. 1. It is to be noted that the displacement of the metal is such that sharp walls and corners are not always formed as shown in FIG. 1. However, the terms parallel flat and inclined as used herein are intended to define the structure of the score shown in the photomicrograph of FIG. 2.

In the preferred form of the invention the included angle a between the sides 14 and 16 is between about 30 to 90 preferably 50. The distance 2 across the width of flat 17 is preferrably 0.002 inch and the distance y from the score face or flat 17 is about 0.003 inch. The width w of the land or ledge 18 is about 0.006 inch.

The scoring tool with the above dimensions was used to score a continuous cast steel sheet having a thickness of about 0.0095 inch. The steel sheet was scored with residuals of about 0.0018 inch residuals without fracture.

This was an improvement over the scores obtained with a convention score tool having an angle of 50 between the side walls. Such conventional score tools were used with the same type of sheet steel and excessive fracturing occured with residuals of about 0.0028 inch. This is an increase of about 0.0010 inch in residual which may adversely affect the opening characteristics of the easy-opening container with which the score is intended to be used.

Referring now to FIG. 3 there is shown another embodiment of the invention. As shown the scoring tool includes a punch 111 and an anvil 12. A scoring rib 113 projects from the punch 111. A pair of inclined side walls 114 and 116 which taper toward a flat scoring face 117 are each formed with a ledge or land 118.

The lands 118 divided the respective side walls 114 and 116 into side wall sections 116a-l1-6b and 114a-114b which are parallel to each other.

The punch 111 is forced into engagement with the sheet metal disposed on the anvil 112 in the same mannet as described in connection with the embodiment of FIG. 1. The rib 113 crushes the surface and forms a score 1138 including a bottom flat 1178 and wall sections 114aS and l14bS and l16aS and ll6bS and ledges 1 188. The ledges or lands l 188 serve to displace additional material above the bottom face of the score during the scoring operation thereby apparently to relieve same of the stress associated with the scoring operation.

What is claimed is:

1. A score formed in sheet of metal comprising a bottom wall, a pair of inclined side walls extending from said bottom wall, and a ledge disposed intermediate the length of at least one of said side walls and interrupting the same.

2. A score as defined in claim 1 wherein a ledge interrupts each of said side walls.

3. The invention of claim 1 wherein said sheet of metal is a panel of a container end closure.

4. The invention of claim 1 wherein the incline of said one side wall is the same below and above said ledge.

5. The invention of claim 1 wherein said ledge is substantially parallel to said bottom wall.

6. The invention of claim 1 wherein said ledge is of a width approximately 3 times the width of said bottom wall.

7. The invention of claim 1 wherein said ledge is of a width of about 0.006 inch.

8. The invention of claim 1 wherein said ledge and an upper part of said one side wall defines an anti-fracture score portion. 

1. A score formed in sheet of metal comprising a bottom wall, a pair of inclined side walls extending from said bottom wall, and a ledge disposed intermediate the length of at least one of said side walls and interrupting the same.
 2. A score as defined in claim 1 wherein a ledge interrupts each of said side walls.
 3. The invention of claim 1 wherein said sheet of metal is a panel of a container end closure.
 4. The invention of claim 1 wherein the incline of said one side wall is the same below and above said ledge.
 5. The invention of claim 1 wherein said ledge is substantially parallel to said bottom wall.
 6. The invention of claim 1 wherein said ledge is of a width approximately 3 times the width of said bottom wall.
 7. The invention of claim 1 wherein said ledge is of a width of about 0.006 inch.
 8. The invention of claim 1 wherein said ledge and an upper part of said one side wall defines an anti-fracture score portion. 